1. Field of the Invention
This invention relates to a virtual local area network (LAN) related to logical configuration management of a LAN and more particularly to a LAN segmentation system for controlling a traffic flow of a LAN appropriately and using transmission media efficiently for improving the utilization factor of the entire network and a logical configuration management system of a LAN for facilitating management of move, change, addition, etc., of computers.
Particularly, the invention relates to a virtual LAN (VLAN) for logical segmentation of a network so as to form a structure independent of a physical world so as to be able to change the network dynamically following business structure change of work groups, projects, etc., of organizations including enterprises based on LAN switching technologies.
Specifically, the invention relates to priority service and QOS (quality of service) guarantee technique for automatically reconfiguring a network in response to move of terminals, etc., and supporting the transmission quality of a transmission band, delay time, etc., on demand.
Specifically, the invention relates to a port segment switching system for setting a common microsegment to a plurality of ports of each switching hub for a plurality of switching hubs.
Specifically, the invention relates to a virtual network switching system for mapping logical network segments to physical traffic segments for enabling dynamic reconfiguration.
Specifically, the invention relates to a virtual network switching system for enabling customization of network configuration, function, and service to suit the user such as a network administrator of a work group or a department in an environment in which a plurality of servers for providing service making good use of resources of various environmental facilities of an enterprise such as network distributed management and building automation (BA) are distributed over a network.
Further, the invention relates to an intelligent building wiring system. It relates to a distributed integrated wiring system for a network for integrating an enterprise network system occupying an important part with communication processing of information communication technology (IT), intelligent building communication, office automation (OA), and BA.
2. Description of the Prior Art
In an in-house network, a host centralized network with channel connection of online transaction terminals centering on a host computer system combining a database server and an application server with a communication control function has been used mainly as a network of an account system of a financial institution or a business system of an enterprise. In addition, in an information system network using a LAN connecting personal computers (PCs) as terminals and a host computer on a TCP/IP protocol basis, a client and centralized server network is a paradigm, wherein most employees connect PCs as their own client machines to the network.
Further, a distributed server and client network has become pervasive together with a catchword of right-sizing. In the network, server machines operate as application servers and database servers of packaged application software replacing a host computer as enterprise servers supporting online transaction and distributed database functions in the operating system of a workstation (WS) server or a PC server and are connected on the network for network computing at the enterprise level or globally replacing a conventional host computer.
Global network computing as seen in a derivative field in which speedy approval is given making free use of servers distributed worldwide supports worldwide enterprise activities in combination with internet and database replication technologies.
In an internet and an intranet as an in-house network, WWW (world-wide web) servers and desktop WWW browsers distributed over the network spring into wide use. Particularly, a database connected to WWW servers can be easily accessed integrally in a GUI (graphical user interface) environment with multimedia of images, data, voice, etc., as an object, thus the demand for the WWW multimedia network is increasing explosively.
Computers become easy to use and personal owing to operating systems and WWW technologies with an excellent GUI and are connected to a network for all employees to share information and immediately providing information for business efficiency improvement and prompt decision making, thereby enhancing intellectual productivity. Thus, business application of information communication technologies moves and an enterprise or an enterprise model is becoming a network-type distribution form. Further, information communication networking technologies support global enterprise activities like virtual enterprises connected by networks. Expandability and innovation that can deal speedily with change in the enterprise activities are increasingly demanded for the network and information communication technologies. At the same time, high speed and high performance are demanded in addition to reliability, integrity, and economy because all persons working in offices, etc., use networks.
To improve intellectual production in offices, a more intelligent network service function making free use of the information communication technologies is demanded in addition to providing the amenities of building facilities such as air-conditioning and sanitary facilities, lighting facilities, and disaster prevention facilities.
Development of higher-performance digital information communication technologies or network and computing machines is pursued with the widespread use of networks and advanced technology innovation for widening and speeding up networks. Further, the product life of the network machine itself is short and the cycle time also becomes short; more advanced new products to which new functions are added appear on the market one after another in a short term and old products are made out-of-date very quickly. On the other hand, for competition between enterprises and innovation of enterprise activities, it becomes necessary to replace old network machines with new network machines keeping up with the state-of-the-art technology innovation in a short time. Thus, it becomes an important challenge to economically provide a migration path for gradual network introduction and machine expansion, enhance network security, and offering intelligent network service.
By the way, for multimedia transmission in an internet or an intranet, an RSVP (resource reservation protocol) for preferentially passing one-way data traffic of stream type of telephone or video conference on a connectionless IP protocol basis is developed and a peer-to-peer network of a video conference system, etc., by IP multicasting at the internet level is also developed. The RSVP itself is not a routing protocol and operates with unicasting and multicasting routine protocols like an internet control protocol occupying the TCP area on the IP. The receiving party issues a transmission quality guarantee (QoS) request. In the router and the host at node, a packet classifier determines an input packet route and QoS, a packet scheduler determines forwarding for each packet, admission control determines whether or not there are sufficient resources to support the requested QoS, and policy control determines whether or not the user is authorized to use the resources. The RSVP itself transmits and handles QoS control parameters as opaque data. The RSVP is designed to be able to be expanded to a very large member, group, and multicast group having topology of a tree structure according to router "soft state" (use of state transition by software).
On the other hand, in a connection-oriented ATM (asynchronous transfer mode) system, development of LAN emulation corresponding to the conventional LAN bridge, MPOA for providing a multiprotocol router on LAN emulation, an IP-over-ATM system for passing the IP on ATM, an IP-over-RSVP system for passing the RSVP on ATM, an IP switching system for switching only the IP on ATM, a 1-PNNI system for routing internet protocols on a private signaling protocol between ATM switches, and ATM-native transmission quality guarantee (QoS) technique is also pursued.
Hitherto, center units of information communication facility machines such as a center line concentrator of LAN and telephones, a BA monitor controller, and electric equipment of a distribution board, etc., in an intelligent building have been gathered at a center of an electric room, etc., under an electric shaft (EPS) to reduce in network maintenance and management costs and provide security. That is, the servers at the enterprise level and important network machines on network management are gathered in the network center and management is centralized in such a manner that a telephone switching system is installed in a switching system room and that a disaster prevention system and a BA central monitor panel are installed in a central monitor room in the building. Subcentral units of information communication facility machines such as a floor line concentrator for controlling information communication terminals, a BA monitor controller, and electric equipment for each floor are installed in a wiring closet on each floor together with a floor distribution frame (floor IDF), etc. Generally, they are mounted on a 19-inch rack from which star wiring is installed to outlets on each floor by an advanced wiring system.
The wires of a machine room subsystem from the network center, the switching system room, and the central monitor room are collected as a trunk at a main distribution frame (MDF). A trunk line wiring subsystem as a backbone is formed from the MDF to the floor IDF in the wiring closet on each floor and wires from the IDF to the terminals or outlets in the floor make up a branch line wiring subsystem. It is ideal to wire from the distribution frame (IDF) to a wall face or floor outlet with a 4-pair twisted pair line at the shortest distance as star connection. The information lines of the trunk line wiring subsystem are housed in the EPS together with a power distribution system extending straight from the bottom floor to the top floor of the building. The room through which the EPS passes on each floor becomes the wiring closet, thus here the wiring closet and the electric shift (EPS) are handled the same.
On a comparatively large floor, a room distribution frame (room IDF) is installed in a work group or on a wall face of a room, etc., and wiring is installed with twisted pair lines using multiple twin cable in room IDF units from the floor IDF in the wiring closet to the room IDFs in the work groups.
Functionally, the wiring from the floor IDF to the room IDFs becomes a form in which the wiring closet is distributed to the floor, thus here is called a floor trunk line wiring system. A room line concentrator for controlling the information communication terminals for each room may be installed in the floor IDF.
In a room, the information terminals such as PCs can be laid out like an island structure in response to desk placement. Thus, the island is called a zone and a zone wiring system for installing a zone wiring box on the floor is also available. Fixed floor wiring is from the floor IDF or room IDF to the zone wiring box and a flexible wiring system is applied from the zone wiring box to a deskside receptacle.
In floor wiring, there is an access floor under which wiring is stored and wiring box storage places are provided combining power wiring for supplying power to the information terminals such as PCs and telephone/LAN information wiring. In LAN wiring, there is a type wherein only passive connectors are built in the zone wiring box and a type wherein a repeater HU having a plurality of several active ports is built in as a zone line concentrator. Deskside information receptacles include those of a type wherein only passive modular connectors are built in and those of a type wherein a table tap repeater hub having several active ports is built in as a deskside line concentrator. Ethernet of collision detection type (CSMA/CD) is often used as a LAN access method that terminals use; in information wiring, as LANs become widespread and the number of terminals increases, the advanced wiring system with twisted pair lines previously used for telephone wiring in USA utilizes a wiring change management function with a cross batch panel of an IDF.
In Ethernet, a 10BASE-T system at a transmission speed of 10 Mb/s with a twisted pair line becomes popular at desktops. Twisted pair lines as floor wiring are gathered in a floor line concentrator installed in a wiring closet and the floor line concentrator is provided with a signal repeater function, is connected to a higher-speed trunk LAN, and is provided with a bridge/router function for segmenting network traffic. A main router connected to the external internet, a switching system connected to telephone lines, a host computer, a file server, and a center line concentrator connected to a high-speed trunk LAN are installed in a network center.
The center line concentrator and floor line concentrator are mounted on a so-called 19-inch rack in the chassis form, box form, stack form, etc. The repeater, the bridge, the router, and the like are connected to each other as multivendors according to a signal system and communication protocol conforming to the standard.
In recent years, Ethernet with twisted pair lines has also been speeded up to 100 Mb/s to 1 Gb/s; the transmission distance with an unshielded twisted pair line (UTP) of the CAT5 grade has become 50-100 m. In the advanced wiring system, although the transmission speed 10 Mb/s is mostly applied for the time being, CAT5-grade unshielded twisted pair lines are used from the beginning in expectation of speeding up for the future or incombustible optical fiber wiring fixedly embedded in a wall, etc., enabling longer-distance, higher-speed transmission is also used partially.
As the number of terminals grows and the use band of each terminal increases, it becomes necessary to improve the line processing capability of each floor line concentrator in addition to speeding up transmission on wiring to enhance traffic throughput and hold the transmission delay time short. A controller chip of an Ethernet switching system utilizing the high-speed data processing capability of a semiconductor processor is commercially available, and a switching hub with a plurality of ports capable of communicate at a transmission speed of 10 or 100 Mb/s independently at the same time is used as a line concentrator. When. such Ethernet switching ports are connected to specific segments in the line concentrator for each port and are filtered based on MAC addresses, they are called port switches or configuration switches; when the ports are filtered to arbitrary segments based on MAC addresses for each port, they are simply called LAN switches. The port or configuration switches and the LAN switches are called layer 2 LAN switches. In a server-client network, connection to the server and connection to the backbone are speeded up. An Ethernet switching hub having the capability of appropriately selecting the port transmission speed in response to traffic in such a manner that connection to the server or connection to the backbone is made on a big pipe of 100 Mb/s and that connection to other ports is made at 10 Mb/s is available. Also, an Ethernet switching hub having a function of automatically recognizing that the terminal connected to each port is at 10 Mb/s or 100 Mb/s is available. If a repeater hub at the transmission speed 10 Mb/s, 100 Mb/s is used as a deskside line concentrator or a zone line concentrator to which one to several terminals are connected, a collision scarcely occurs and an area connected to the repeater hub and bridged by switch port is called a microsegment.
The microsegment is defined locally and is positioned as a subdivided segment in a virtual LAN segment; it is a unit in which several PCs (personal computers) can share media without a collision. In a configuration switching device, microsegments are set in port units and are reconfigured. The virtual LAN segment is defined on an upper layer of a LAN system and is common to sites, buildings, and floors covered by network management; the microsegment is defined locally on a low-order layer of a configuration switching device installed in a wiring closet on each floor and is closed in the configuration switching device. A single segment of wiring only or repeater connection is between the configuration switching device in the wiring closet and a desktop.
Since most of traffic concentrates on network backbone (trunk) and server connection, high-speed expandability is required and expansion to Ethernet at 100 Mb/s to 1 Gb/s is intended for the sever connection. A backbone of a frame riser with a 100-Mb/s LAN switch installed in a center line concentrator and a LAN switch with a 100-Mb/s interface installed in a floor line concentrator is used. Further, if expandability and transmission quality guarantee (QoS) are required, a backbone of a cell riser with an ATM switch installed in a center line concentrator and a LAN switch with an ATM interface installed in a floor line concentrator is used.
Hitherto, with an FDDI system used for a trunk LAN, a main router with an FDDI interface connected to an external system has been installed in a center line concentrator, an FDDI-Ethernet bridge router has been placed in a floor line concentrator, frame conversion between the FDDI and Ethernet has been executed, and segmentation has been made according to a routing protocol. However, with the widespread use of the layer 2 LAN switches, a system is available wherein a main router connected to an external system and a layer 2 LAN switch are installed in a center line concentrator, a layer 2 LAN switch is installed in a floor line concentrator, a backbone is made a single subnet flat for a routing protocol, LAN switch segments are made broadcast domains to form an independent LAN, and segment-to-segment traffic is passed through the main router. Further, an implicit VLAN with segments entered in a table as a MAC address group to form implicit virtual LAN segments and an explicit VLAN forming explicit virtual LAN segments with a tag identifiable for each group inserted in a packet are available. In such layer 2 VLANs with the layer 2 LAN switches, the switch filtering function can be used to arbitrarily set segments independent of physical wiring across floor line concentrators, enabling segmentation in response to the enterprise organization or work groups. To form layer 2 LAN switches by ATM LAN emulation, a virtual LAN is formed on VPI/VCI connection; transmission quality guarantee (QoS) is not provided in the LAN emulation.
However, to segment a flat subnet into layer 2 subnets, every broadcast concentrates on the main router and segment-to-segment traffic also concentrates on the main router. Thus, it is feared that the processing capability of the main router will becomes a bottleneck or a one-point failure point and that a failure of the main router will cause the entire network to stop.
When the servers managed in a centralized manner in the network center are accessed or overlapped segments across segments are formed, communication traffic across layer 2 LAN switch segments increases. Then, a switch called a layer 3 LAN switch filtered based on the routing protocol address or the protocol type has been developed for floor line concentrators. With the layer 3 LAN switch, layer 3 virtual network segments based on logically defined protocol addresses independently of physical wiring like MAC addresses or ports are formed and may be called virtual subnet. Since the layer 3 LAN switch contains a router function, traffic across layer 2 subnets can also be directly switched not via the main router; subnets rather than flat subnets can be classified according to management policy or a fire wall for the routing protocol can be provided for enhancing security. If the layer 3 LAN switch is formed in an MPOA system on ATM LAN simulation, standardization is not yet complete, thus the layer 3 LAN switch may be installed under specifications proper to each vendor and limited transmission quality guarantee (QoS) is also provided. A backbone LAN system of routing between ATM switches in an I-PNNI system and using a layer 3 LAN switch as the edge LAN switch is also developed.
An IP switch system or tag switch system on which recent attention is focused is a layer 3 LAN switch on an ATM switch developed uniquely by a LAN vendor for which standardization is proposed by the LAN vendor.
High performance of center and floor line concentrators to a higher-end system moves to a layer 2 virtual LAN and a layer 3 virtual network integrating the routing and switching technologies to deal with an increase in backbone traffic.